The present invention relates to a semiconductor device, and more particularly to a semiconductor device that is capable of correctly transferring signals at high speed.
Conventionally, a wiring pattern of printed conductor lines and the like is formed an a product system substrate. A plurality of semiconductor chips are mounted an the system substrate, and electrode pads are formed on the semiconductor chips for transferring electric signals. The electrode pads are electrically connected to lead frames by bonding wires. The semiconductor chip, the bonding wires and one end of the lead frames are sealed with resin. On the other hand, the other end of the lead frames is connected to the wiring pattern by soldering or pressure bonding. Electrical signals are transferred (inputted and outputted) between the semiconductor chips through the wiring pattern and the lead frames.
In the conventional semiconductor device described above, digital signals are generated by turning ON and OFF of electrical signals, and such signals are transferred.
As a result, there an problems in that the semiconductor device is likely to be affected by noises that may result from factors such as higher frequency, higher operation speed and lower voltage (2V) operation. Also, malfunctions may possibly occur due to other factors such as voltage fluctuations.
Furthermore, in the conventional semiconductor device described above, portions of the lead sections that protrude from the mold resin (i.e., the semiconductor package) are connected to the wiring pattern on the system substrate by soldering or pressure bonding, and electrical signals that are transferred by the wiring pattern are inputted in or outputted from the semiconductor chips.
As a result, the electrical signals are substantially influenced by physical properties of transfer elements (physical properties of copper or the like) of the wiring pattern. Therefore, there is a problem in that it is difficult to continuously maintain the original characteristics of the signals. In other words, harmful effects may be created by the influences of the physical properties of adjacent wirings, such as wiring capacitance and the like. As a result, for example propagating signals may be blunted, their amplitudes may become unstable, and devices in succeeding stages may malfunction.
In particular, circuits for clock signals that are inputted in and outputted from the semiconductor device must be designed in consideration of the harmful effects. Also, since electrical influences among adjacent signal lines cannot be ignored. Malfunction protection circuits and other signal controls may need to be implemented. Moreover, the leads that protrude from the semiconductor package have a limited degree of freedom with respect to their length and positions, and therefore, the leads can only be connected to limited areas on the system substrate.
Therefore, it is an object of the present invention to provide a semiconductor device that can accurately transmit signals at high speed.
In accordance with one embodiment of the present invention, a semiconductor device includes a semiconductor chip, a light-receiving element formed on the semiconductor chip for receiving optical signal, and an optical signal transfer device connected to the light-receiving element for transferring the optical signal into the semiconductor chip.
In accordance with this embodiment, the optical signal transfer device is connected to the semiconductor chip through the light-receiving element, such that optical signals are used as signals that are inputted in the semiconductor chip. Optical signals have a smaller attenuation of signal amplitude and have a higher transfer speed compared to electrical signals. Therefore, correct signal transfer becomes possible, and thus signals can be correctly transferred at high speed.
The optical signal transfer device may be formed from an optical fiber, such as, for example, a glass fiber.
Also, the semiconductor device may further include a package that seals the semiconductor chip and a portion of the optical fiber.
Also, the semiconductor chip may be mounted on a mounting substrate.
Also, in accordance with another embodiment of the present invention, a semiconductor device includes a mounting substrate, an optical signal transfer device disposed in the mounting substrate for transferring optical signals, a plurality of semiconductor chips mounted on the mounting substrate, and a light-receiving element connected to the optical signal transfer device for receiving optical signals, wherein signals are transferred among the plurality of semiconductor chips by the optical signal transfer device.
Furthermore, in accordance with another embodiment of the present invention, a semiconductor device includes a semiconductor chip, a light-receiving element formed on the semiconductor chip for receiving optical signals, and an optical signal transfer device connected to the light-receiving element for transferring signals from an arithmetic processing apparatus as optical signals into the semiconductor chip.
In accordance with this embodiment, the optical signal transfer device is connected to the semiconductor chip through the light-receiving element, such that optical signals are used as signals that are inputted from the arithmetic processing apparatus in the semiconductor chip. Optical signals have a smaller attenuation of signal amplitude and have a higher transfer speed compared to electrical signals. Therefore, correct signal transfer becomes possible, and thus signals can be correctly transferred at high speed.
In particular, when clock signals are used as signals that are inputted from the arithmetic processing apparatus in the semiconductor chip, phase shift in the clock signals can be avoided, and highly accurate clock signals can be transferred to the semiconductor chip.
Also, the optical signal transfer device may be provided in a mounting substrate on which the semiconductor chip is mounted. For example, the optical signal transfer device may be embedded in the mounting substrate.
Also, a light-emitting element surface that is formed on the mounting substrate or within the mounting substrate may, be used as the optical signal transfer device. In other words, for example, the light-emitting element surface is formed on the mounting substrate, such that the entire surface of the mounting substrate may irradiate light in response to inputted optical signals. As a result, the optical signal transfer device can be disposed anywhere in the mounting substrate without regard to the mounting location of the semiconductor chip within the mounting substrate.
Alternatively, instead of forming a light-emitting element surface over the entire surface of the mounting substrate, the optical signal transfer device may be formed in a lattice configuration, and disposed in the mounting substrate.
In this instance, the light-receiving element in a convex shape may be formed on the semiconductor chip on a side thereof that is opposite to the mounting substrate. The light-receiving element may be inserted in the optical signal transfer device that is disposed in a plane configuration or a lattice configuration to thereby connect the light-receiving element to the optical signal transfer device. As a result, the light-receiving element and the optical signal transfer device can be readily and securely connected to each other.